Doesn't say anything about banning people from worshiping their gods, in fact it says they pretty much worshiped the same gods. It does mention the destruction of temples, but then the entire city was destroyed. The Assyrians took the idol of Marduk back with them to Nineveh, but they didn't destroy it. Incidentally, Deutero-Isaiah predicted that the Persians would destroy the Babylonian Temple, just as the Babylonians had destroyed their own. Didn't happen. Cyrus conquered Babylon thanks to the priests opening the gates and he claimed to be acting in the name of Marduk. Although a Zoroastrian himself he seemed perfectly happy to have his subjects pray for his health and welfare to the god of their choice.